Problem in the round(x) Function

[RABO2320]

Hi
I've encountered a problem with the round (x) function.
The function after compiling on the chip does not work properly on the negative part of the numbers.
This bug exists in both AVR and PIC compilers.

Examples of both AVR and PIC (with Proteus file):

Pic.rar

(25.45 KiB) Downloaded 187 times

Avr.rar

(19.76 KiB) Downloaded 173 times

Thanks

[kersing]

Please describe what your results are and what you expect to see.

[RABO2320]

Results obtained:

round(-0.5) = 0
or
round(-1) = 0
or
round(-1.3) = 0
and
round(-1.7) = -1

These results are wrong on the chip but in Flowcode the results are correct

[RABO2320]

Hi
I've encountered a problem with the round (x) function.
The function after compiling on the chip does not work properly on the negative part of the numbers.
This bug exists in both AVR and PIC compilers.
Results obtained:

round(-0.5) = 0
or
round(-1) = 0
or
round(-1.3) = 0
and
round(-1.7) = -1

These results are wrong on the chip but in Flowcode the results are correct.

Examples of both AVR and PIC (with Proteus file):

Pic.rar

(25.45 KiB) Downloaded 172 times

Avr.rar

(19.76 KiB) Downloaded 162 times

[RABO2320]

No one to answer?

[LeighM]

What is your expected result?
Looks like we simply add 0.5 (effectively rounding to nearest integer, for positive numbers at least.
Do you want rounding up, down, or towards zero?
If you have a project that expects a particular outcome you might need to create your own macro/function to do this.

[Benj]

Yes it looks like we round up.

2.0 = 2
1.5 = 2
1.0 = 1
0.5 = 1
0.0 = 0
-0.5 = 0
-1.0 = 0
-1.5 = 1
-2.0 = 1
-2.5 = 2

Here is the code.

Code: Select all

#define flt_round(f) ((long)((f) + 0.5))

Maybe the Floor function would do more as you expect?

[RABO2320]

Hi benj
The round (x) function must be the result of negative numbers such as positive numbers:
for example:
1.5 = 2
1.0 = 1
0.5 = 1
0.0 = 0
-0.5 = -1
-1.0 = -1
-1.5 = -2
-2.0 = -2
-2.5 = -3

But the floor function:
1.2 = 1
1.5 = 1
1.8 = 1
0.5 = 0
0.0 = 0
-0.5 = 0
-1.0 = -1
-1.5 = -1
-1.8 = -1
-2.5 = -2

The Flowcode works correctly but does not work on the chip after compiling .

[Benj]

Hello,

This problem should now be fixed with the latest updates. Help -> Check for updates.